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This study will test the hypothesis that a wearable automated bionic pancreas system that automatically delivers both insulin and glucagon can improved glycemic control vs. usual in the outpatient environment.

Condition or disease

Intervention/treatment

Type 1 Diabetes

Device: Bi-homonal Bionic PancreasOther: Usual care

Detailed Description:

The study population will be volunteers with type 1 diabetes who are 21 years of age or older. The setting will be an outpatient environment in a three square-mile area on the Boston Peninsula (see Appendix A). Volunteers will stay in a hotel adjacent to the MGH campus at night and will have free activity during the day within the specified geographic area. They will determine the timing and nature of their meals from local restaurants, with food brought from home, or food kept in their hotel room, which will have a small refrigerator. They will have the opportunity to exercise as they wish in their choice of two gyms. There will be minimal scheduling constraints, limited only by an 11:00 PM curfew and morning departure time from the hotel of no earlier than 7:00 AM. They will be able to work if they wish as long as that can be done within the geographical constraints (e.g. if they work in the downtown Boston area or can "work from home" or have meetings at a conference room in the hotel or at a restaurant). During the entire experiment they will be closely monitored by study staff (RN, NP, or MD) around the clock. They will remain within direct line of sight and no more than a short distance away from study staff during the daytime for safety. During the night they will be continuously monitored via BG telemetry from a nearby hotel room and study staff will be able to enter their rooms quickly, should that become necessary. During the night, when volunteers will remain in their rooms, one study staff member will monitor up to two volunteers at a time.

Capillary BG will be tested every two hours during the day using a highly accurate, laboratory equivalent meter (HemoCue, selected for maximum data integrity) and venous BG will be tested every 30 minutes overnight using an autosampling device (GlucoScout). Continuous glucose monitoring (Dexcom G4) will be done throughout the study period. Photos and menu information, if available, will be documented for each meal and snack by the escort and estimates of carbohydrate intake will be estimated later from this information by a nutritionist. The type and level of activity being performed by the volunteers (e.g. lying, sitting, standing, walking, running) will be documented in 15 minute intervals by the study staff escort. Additional data will be collected using an accelerometer. During exercise, the type and duration of exercise, and, depending on the kind of activity, the heart rate (recorded using a Polar heart rate monitor) will be documented every 15 minutes and point-of-care blood glucose will be documented every 30 minutes.

Closed-loop blood glucose control with a bi-hormonal bionic endocrine pancreas designed by Edward Damiano and Firas El-Khatib of Boston University. The device will deliver insulin lispro (Humalog) and glucagon based on blood glucose levels estimated by a continuous glucose monitoring device (Dexcom G4 Platinum) and a proprietary dosing algorithm. Blood glucose control will be automated for 5 days during which volunteers will sleep in a hotel and roam freely in downtown Boston during the day. There will be no restrictions on diet or exercise.

Device: Bi-homonal Bionic Pancreas

A computer algorithm will automatically deliver insulin lispro and glucagon based on the signal from a minimally invasive continuous glucose monitor.

Other Name: Boston University Bionic Pancreas

Active Comparator: Usual Care

Usual care for 5 days (insulin pump therapy according to usual practice), volunteers will sleep at home and maintain their usual schedule during the day, there will be no restrictions on diet or exercise, they will wear a blinded CGM

Average Blood Glucose (Co-primary Outcome) [ Time Frame: 5 days of closed-loop control ]

Average blood glucose during the closed-loop control period as determined from HemoCue capillary measurements (daytime+nightime) and GlucoScout venous measurements (nighttime).

Percentage of Time Blood Glucose Values Less Than 70 mg/dl (Co-primary Outcome) [ Time Frame: 5 days ]

Percentage of time blood glucose values during the closed-loop control period less than 70 mg/dl determined from HemoCue capillary measurements (daytime) and GlucoScout venous measurements (nighttime) during day 1-5.

During usual care (open loop), blood sugars were not checked through GlucoScout or HemoCue (as per usual care fashion) and so were not compared to bionic pancreas (closed loop) arm

Secondary Outcome Measures
:

Average BG During the Closed-loop Control Period as Determined From All HemoCue Measurements Taken During the Daytime and All Scheduled GlucoScout Measurements During the Nighttime. [ Time Frame: 5 days ]

During usual care (open loop), blood sugars were not checked through GlucoScout or HemoCue (as per usual care fashion) and so were not compared to bionic pancreas (closed loop) arm

Percentage of the Subset of BG Values Less Than 70 mg/dl as Determined From All All HemoCue Measurements Taken During the Daytime and Scheduled GlucoScout Measurements Taken During the Nighttime. [ Time Frame: 5 days ]

Difference in the Average BG Between the Closed-loop Control Period and the Usual Care Period. [ Time Frame: 5 days ]

Difference in the Percentage of the Above Subset of BG Values Between the Closed-loop Control and Usual Care Periods Less Than 70 mg/dl. [ Time Frame: 5 days ]

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Diabetes managed using an insulin infusion pump and rapid- or very-rapid-acting insulins including insulin aspart (NovoLog), insulin lispro (Humalog), and insulin glulisine (Apidra) for at least three months prior to enrollment

Otherwise healthy (mild chronic disease such as asthma, hypertension, and depression will be allowed if well controlled)

Exclusion Criteria:

Unable to provide informed consent

Unable to comply with study procedures

Total daily dose (TDD) of insulin that is > 1.5 U/kg

Pregnancy (positive urine HCG), breast feeding, plan to become pregnant in the immediate future, or sexually active without use of contraception.